TABLE 3.
Influence of mexR and PA3719 mutations on the antibiotic susceptibility of P. aeruginosa
| Strain | MexR protein expressed | PA3719 protein expressed | MIC (μg/ml) of:
|
||||
|---|---|---|---|---|---|---|---|
| Carbenicillin | Chloramphenicol | Novobiocin | Norfloxacin | Nalidixic acid | |||
| K767 | Wild type | None | 64 | 32 | 128 | 0.5 | NDc |
| K1491 | None | None | 512 | 256 | 1,024 | 2 | ND |
| K2519 | None | Wild type | 512 | 256 | 1,024 | 2 | ND |
| K1491(pDSK519)a | None | None | 512 | 128 | 1,024 | 2 | ND |
| K1491(pLC66) | Wild type | None | 32 | 16 | 128 | 0.5 | ND |
| K1491(pLC67) | L35P | None | 64 | 16 | 128 | 0.5 | ND |
| K1491(pLC68) | I104F | None | 128 | 32 | 128 | 0.5 | ND |
| K1491(pLC69) | M112T | None | 128 | 32 | 128 | 0.5 | ND |
| K1491(pLC70) | L135F | None | 64 | 16 | 128 | 0.5 | ND |
| K1491(PLC71) | L28P | None | 512 | 128 | 1,024 | 2 | ND |
| K1491(pLC72) | L75P | None | 512 | 128 | 1,024 | 2 | ND |
| K2519(pDSK519)a | None | Wild type | 512 | 128 | 1,024 | 2 | ND |
| K2519(pLC66) | Wild type | Wild type | 256 | 128 | 512 | 2 | ND |
| K2519(pLC67) | L35P | Wild type | 64 | 32 | 64 | 0.5 | ND |
| K2519(pLC68) | I104F | Wild type | 64 | 32 | 128 | 1 | ND |
| K2519(pLC69) | M112T | Wild type | 64 | 16 | 64 | 0.5 | ND |
| K2519(pLC70) | L135F | Wild type | 128 | 64 | 128 | 1 | ND |
| K2519(PLC71) | L28P | Wild type | 512 | 128 | 1,024 | 2 | ND |
| K2519(pLC72) | L75P | Wild type | 512 | 128 | 1,024 | 2 | ND |
| K2276 | Wild type | None | 32 | ND | ND | ND | 128 |
| K2276(pMMB206)b | Wild type | None | 32 | ND | ND | ND | 128 |
| K2276(pSF001) | Wild type | Wild type | 128 | ND | ND | ND | 512 |
| K2276(pSF002) | Wild type | W45A | 32 | ND | ND | ND | 128 |
| K2276(pSF003) | Wild type | L36P | 32 | ND | ND | ND | 128 |
a
Plasmid pDSK519 derivatives encoding the MexR proteins indicated were introduced into P. aeruginosa strains K1491 (ΔmexR) and K2519 (nalC ΔmexR), and antimicrobial susceptibility was assessed. PA3719 is expressed only in K2519, as a result of the nalC mutation.
b
Plasmid pMMB206 derivatives encoding the PA3719 proteins indicated were introduced into P. aeruginosa strain K2276 (nalC ΔPA3719), and antimicrobial susceptibility was assessed.
c
ND, not determined.